1. Field of the Invention
The invention relates to a dual-wall container having a color changing capability. The invention also relates to a dual wall container that includes an outer wall which is at least partially substantially transparent and/or translucent and an inner wall that includes at least one symbol covered by a coating and/or a layer of a thermochromatic composition. When the inner wall experiences or senses a temperature change, e.g., heating above ambient or cooling below ambient, the thermochromatic composition reacts by changing color, e.g., by becoming substantially colorless, substantially transparent, or substantially translucent, thereby increasing the contrast between the at least one symbol and the inner wall. This, in turn, renders the at least one symbol substantially more visible through the outer wall. The invention also relates to a method of making the container.
2. Discussion of Background Information
Containers utilizing dual-walls and/or color changing capabilities are known. US 2005/0242103, for example, discloses a drinking cup includes an inner wall with an outer surface and an inner surface. The inner wall includes a thermo-chromatic substance that exhibits a color variance corresponding to a temperature variance in a beverage in the cup that is in contact with the inner wall. An outer wall is disposed about the inner wall that has a transparent area adapted to permit a visual perception of at least a portion of the color variance of the thermo-chromatic substance in or on the inner wall through the outer wall. A thermal insulation layer is disposed between the inner wall and the outer wall (see Abstract). U.S. Pat. No. 6,921,179 discloses a drinking vessel is provided with an insulated wall structure including an inner wall, an outer wall, and a void between the inner and outer walls providing an insulative barrier for maintaining the temperature of the liquid contents within a desired range for extended periods of time, while also preventing the formation of condensation on the outside of the vessel. Luminescent elements, such as shapes, letters, numbers or designs, are applied to the insulated wall structure to enhance visibility of the drinking vessel and the level of liquid beverage contents when in dark or low light conditions. In an alternative embodiment, the luminescent material is incorporated into the composition of the wall structure during the molding process. A removable lid may be provided for covering the open top of the drinking vessel. In one embodiment, the drinking vessel and removable top lid are structured and disposed to provide a child's sip cup, wherein the lid includes an integrated sip spout and valve for resisting spills (see Abstract).
However, such containers do not utilize the unique combination of features of the instant invention. In particular, they do not utilize e.g., a dual-wall container having an outer wall which is at least partially substantially transparent and/or translucent and an inner wall that includes at least one symbol covered by a coating and/or a layer of a thermochromatic composition, wherein, when the inner wall experiences or senses a temperature change, e.g., heating above ambient, the thermochromatic composition reacts by changing color, e.g., by becoming substantially colorless, transparent or translucent, thereby increasing the contrast between the at least one symbol and the inner wall, and whereby the at least one symbol is rendered substantially more visible through the outer wall.